What is the recommended maintenance dose of propranolol (beta blocker) for hyperthyroidism?

Propranolol Dosing for Hyperthyroidism

The recommended maintenance dose of propranolol for hyperthyroidism is 160-320 mg per day, with an average dose of 160 mg/day being effective for most patients. 1

Initial Dosing and Titration

• Start with 40-80 mg per day divided into 2-3 doses, then gradually increase to the maintenance dose 1, 2
• Titrate the dose upward every 4-7 days based on heart rate response, with the goal of maintaining resting heart rate below 75 beats per minute 2
• For most patients, clinical compensation (control of symptoms) requires 240-400 mg/day 3
• Some patients may not achieve adequate symptom control even with doses up to 480 mg/day 3

Dosing Considerations

• Individualize dosing based on:
  • Heart rate response (target resting heart rate <75 beats/minute) 2
  • Symptom control (tremor, sweating, palpitations) 1
  • Patient weight and metabolism (hyperthyroid patients may require higher doses) 2
• Plasma levels of propranolol correlate with clinical effects and biochemical changes (decrease in T3 and increase in reverse T3) 2

Administration

• Divide daily doses into 2-3 administrations for conventional tablets 1, 2
• Once-daily dosing is possible with long-acting propranolol formulations (Inderal LA) 4
• When switching from conventional tablets to extended-release capsules, retitration may be necessary as they are not simple mg-for-mg substitutes 5

Monitoring

• Monitor heart rate and blood pressure during dose titration 6
• Clinical improvement is primarily due to beta-adrenergic blockade rather than effects on thyroid hormone metabolism 3
• Propranolol effectively neutralizes symptoms of autonomic hyperactivity (sweating, tremor, tachycardia) without significantly affecting thyroid function 1

Duration of Treatment

• Propranolol can be used for rapid preparation of thyrotoxic patients for surgery (within 24 hours for elective procedures) 1
• For long-term management, propranolol may be continued until definitive treatment (surgery, radioactive iodine) takes effect or until remission occurs with antithyroid drugs 1

Special Considerations

• Propranolol may mask symptoms of hypoglycemia, which is particularly concerning in susceptible patients 7
• Abrupt discontinuation should be avoided to prevent rebound hypertension or tachycardia 7
• Contraindications include heart block, decompensated heart failure, asthma, and hypotension 7

Therapeutic Failure

• If clinical response is inadequate, consider increasing the dose up to 320-400 mg/day 3, 2
• Therapeutic failure may be due to suboptimal dosing rather than drug ineffectiveness 2
• A small percentage of patients may not respond adequately even to high doses 3